Magnetic energy storage

Magnetic energy storage has become the foundation for near time and longer range electric utility applications and for current induction in the plasma of fusion devices. The fusion program embraces low loss superconductor strand development with integration into cables capable of carrying 50 kA in pulsed mode at high fields. This evolvement has been paralleled with pulsed energy storage coil development and testing from tens of kJ at low fields to a 20 MJ prototype tokamak induction coil at 7.5 T. Energy transfer times have ranged from 0.7 ms to several seconds. Electric utility magnetic storage for prospective application is for diurnal load leveling with massive systems to store 10 GWh at 1.8 K in a dewar structure suported on bedrock underground. An immediate utility application is a 30 MJ system to be used to damp power oscillations on the Bonneville Power Administration electric transmission lines. An off-shoot of this last work is a new program for electric utility VAR control with the potential for use to suppress subsynchronous resonance. Pulsed magnetic energy storage is not a widely developed technology. Current work is done almost exclusively in Japan and the United States. This paper does not cover past work or completed studies but presents work in progress, work planned, and recently completed unusual work.